Expandable lockout apparatus for a subsurface safety valve and method of use

ABSTRACT

In one aspect of the invention, a locking assembly for a wellbore valve is provided comprising a cylindrical sleeve insertable into an interior of the valve. After insertion into the valve, the body is expanded into interference with a closing mechanism of the valve, thereby locking the valve in an open position.

RELATED APPLICATIONS

[0001] This application claims priority to co-pending provisional U.S.patent application Ser. No. 60/239,506, filed Oct. 11, 2000, entitled“Expandable Lockout Apparatus For A Subsurface Safety Valve And MethodOf Use”, which is hereby incorporated by reference in its entirety.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The invention relates to methods and apparatus for locking awellbore valve in an open position. More particularly, the inventionrelates to methods and apparatus for permanently locking a subsurfacesafety valve in an open position through the use of expandable tubulars.

[0004] 2. BACKGROUND OF THE RELATED ART

[0005] For oil and gas wells, especially those that operate offshore,redundant safety devices typically include a valve located about 500feet below the ocean mud line sealably connected to the productiontubing string through which production fluids pass. The valve, typicallyreferred to as a subsurface safety valve, ensures that if the fluidconduit between the ocean floor and the platform is disrupted (by apassing vessel for instance) that the flow of production fluid from thesub-sea well head will be cut off and the ocean will not be contaminatedwith production fluid. If the subsurface safety valve malfunctionsduring its operational life, it may become necessary to permanently lockout the valve in an open position. This is particularly necessary whenthe safety valve has malfunctioned and closed, commonly due to a controlline break or hydraulic chamber leak. The most common type of subsurfacesafety valve in use in subterranean wells today is the “surfacecontrolled subsurface safety valve”, commonly and hereinafter referredto as an SCSSV. SCSSVs are required by regulatory agencies in alloffshore wells worldwide. SCSSVs may also be used in land wells wherethe risk of wellhead damage and uncontrolled blowout of the well ishigh. Examples of subsurface safety valves include flapper (as shown inFIG. 6), ball (as shown in FIG. 7), and annulus type valves. Safetyvalves are typically actuated by a reciprocating flow tube or choke. Inthe case of a flapper type valve, the flapper pivots about a hinge toclose and block the flow of fluid through the valve. In essence, SCSSVsare “normally closed” downhole valves which are operated by pressurizedhydraulic fluid in a small diameter control line extending from anactuator integral to the valve to a control panel on the earth'ssurface. Pressure in the control line exerted by the control panel holdsthe SCSSV in the open position, permitting fluid to pass through thevalve and to the surface of the well for collection. Disruption of thatpressure for any reason causes the valve to close. For example, if acontrol line or hydraulic seal failure occurs, loss of hydraulicpressure causes inadvertent closure of the flapper.

[0006] Valves, including SCSSVs, may be held in an open position byplacing a spring metal band which expands from a contracted, run-inposition to a radially enlarged locking position adjacent the flapperthereby holding the valve member open. For example, U.S. Pat. No.4,577,694, which is hereby incorporated by reference, discloses arunning tool that holds a metal band spring in the collapsed positionfor placement in the well. When released, the spring expands intocontact with the valve member, thereby holding it in the open position.One disadvantage to a metal band spring is that hydrocarbons flowingpast the metal band spring cause eddies and low pressure areas that cancause the spring to inadvertently collapse and flow upward withproduction. This action can permit the “permanently locked out” SCSSV toinadvertently shut, thereby stopping the flow of hydrocarbons from thewell. This results in costly remedial workover operations and lostproduction.

[0007] Other methods of locking out the SCSSV include incorporation of alockout device integrally into a valve actuating mechanism. However,this solution complicates the design and adds to the total cost of thevalve. An example of this type of lockout mechanism is described in U.S.Pat. No. 4,624,315, which is hereby incorporated by reference. Becauseof the high degree of reliability and longevity of modern SCSSVs, theneed arises very infrequently for locking most SCSSVs open. Furthermore,the integral lock open mechanism has an adverse effect on thereliability of the SCSSV by being continuously subjected to subsurfacewell conditions during normal operations. As such, it may be damaged,corroded or stuck in the retracted position, preventing a necessary lockopen operation when required.

[0008] Insertable locking devices for safety valves are also hampered bythe physical characteristics of wellbores. Wellbores and insidediameters thereof vary greatly from well to well. Also, the insidediameter of a wellbore may vary at different depths. The “drift”diameter of a wellbore refers to a maximum diameter of a length of barthat will pass unimpeded through the inside diameter of a wellbore. Anyinsertable locking device must therefore meet limitations in spaceinherent in a particular wellbore.

[0009] One attempt to compensate for variable physical characteristicsof a wellbore has been to utilize expandable tubular technology. Bothslotted and solid tubulars can be expanded in situ to enlarge a fluidpath through the tubular and also to fix a smaller tubular within theinner diameter of a larger tubular therearound. Tubulars are expanded bythe use of a cone-shaped mandrel or by an expansion tool withexpandable, fluid actuated members disposed on a body and run into thewellbore on a tubular string. During expansion of a tubular, the tubularwalls are expanded past their elastic limit. Examples of expandabletubulars include slotted screen, joints, packers, and liners. FIGS. 1aand 1 b are perspective views of an exemplary expansion tool 100 andFIG. 1c is an exploded view thereof. The expansion tool 100 has a body102 which is hollow and generally tubular with connectors 104 and 106for connection to other components (not shown) of a downhole assembly.The connectors 104 and 106 are of a reduced diameter (compared to theoutside diameter of the longitudinally central body part 108 of the tool100), and together with three longitudinal flutes 110 on the centralbody part 108, allow the passage of fluids between the outside of thetool 100 and the interior of a tubular therearound (not shown). Thecentral body part 108 has three lands 112 defined between the threeflutes 110, each land 112 being formed with a respective recess 114 tohold a respective roller 116. Each of the recesses 114 has parallelsides and extends radially from the radially perforated tubular core 115of the tool 100 to the exterior of the respective land 112. Each of themutually identical rollers 116 is near-cylindrical and slightlybarreled. Each of the rollers 116 is mounted by means of a bearing 118at each end of the respective roller for rotation about a respectiverotational axis which is parallel to the longitudinal axis of the tool100 and radially offset therefrom at 120-degree mutual circumferentialseparations around the central body 108. The bearings 118 are formed asintegral end members of radially slidable pistons 120, one piston 120being slidably sealed within each radially extended recess 114. Theinner end of each piston 120 (FIG. 1a) is exposed to the pressure offluid within the hollow core of the tool 100 by way of the radialperforations in the tubular core 115. In this manner, pressurized fluidprovided from the surface of the well, via a tubular, can actuate thepistons 120 and cause them to extend outward and to contact the innerwall of a tubular to be expanded.

[0010] Therefore, a need exists to provide a method and apparatus forpermanently holding open the SCSSV by a mechanism which is entirelyseparate from the SCSSV mechanism, and one which would not tend to flowout of position during production operations. Additionally, a needexists to provide a lockout sleeve device utilizing expandable tubulartechnology which can be subsequently inserted in the well conduit onlywhen it becomes necessary to permanently lock the SCSSV in an openposition.

BRIEF SUMMARY OF THE INVENTION

[0011] In one aspect of the invention, a locking assembly for a wellborevalve is provided comprising a cylindrical sleeve insertable into aninterior of the valve. After insertion into the valve, the body isexpanded into interference with a closing mechanism of the valve,thereby locking the valve in an open position.

[0012] In another aspect, a method and apparatus for locking out asafety valve in a wellbore is provided in which a tubular, or a lockoutsleeve, having an outer diameter substantially equal to or less than adrift diameter of the wellbore and an expansion tool are placed in thewellbore. The safety valve is located and the lockout sleeve andexpansion tool are landed adjacent the safety valve. With the valve inan open position, the lockout sleeve and the expansion tool arepositioned within an inner diameter thereof. The expansion tool isenergized causing extendable members therein to extend radially tocontact an inner diameter of the lockout sleeve. The lockout sleeve isexpanded into substantial contact with the inner diameter of the safetyvalve, wherein the inner diameter of the expanded lockout sleeve issubstantially equal to or greater than the drift diameter of thewellbore.

[0013] In another aspect, a method for locking out a safety valve in awellbore is provided in which a tubular, or lockout sleeve, having anouter diameter substantially equal to or less than a drift diameter ofthe wellbore and an expansion tool are placed in the wellbore. Thelockout sleeve and expansion tool are landed adjacent the safety valveand a flow tube disposed within the safety valve is located. With thevalve in an open position, the lockout sleeve and the expansion tool arepositioned within an inner diameter thereof. The expansion tool isenergized causing extendable members therein to extend radially tocontact an inner diameter of the lockout sleeve. The lockout sleeve isexpanded into substantial contact with the inner diameter of the safetyvalve adjacent the flow tube, wherein the inner diameter of the expandedlockout sleeve is substantially equal to or greater than the driftdiameter of the wellbore.

[0014] In yet another aspect, an apparatus for locking out a safetyvalve in a wellbore is provided having a tubular, or lockout sleeve,with an outer diameter substantially equal to or less than a driftdiameter of the wellbore. Preferably, the lockout sleeve has one or moresurface features. The lockout sleeve is made of a ductile material andthe surface features may be slots, holes, ovals, diamonds, perforations,or a combination thereof. Further, an inner diameter of the lockoutsleeve is expandable to a diameter substantially equal to or greaterthan the drift diameter of the wellbore.

BRIEF DESCRIPTION OF THE DRAWINGS

[0015] So that the manner in which the above recited features,advantages and objects of the present invention are attained and can beunderstood in detail, a more particular description of the invention,briefly summarized above, may be had by reference to the embodimentsthereof which are illustrated in the appended drawings.

[0016] It is to be noted, however, that the appended drawings illustrateonly typical embodiments of this invention and are therefore not to beconsidered limiting of its scope, for the invention may admit to otherequally effective embodiments.

[0017]FIG. 1a is a perspective view of an expansion tool;

[0018]FIG. 1b is a perspective end view in section thereof;

[0019]FIG. 1c is an exploded view of the expansion tool;.

[0020]FIG. 2 is a perspective view of an embodiment of an unexpandedlockout sleeve according to the invention;

[0021]FIG. 3 is a perspective view of the embodiment shown in FIG. 2 inan expanded state;

[0022]FIG. 4 is a section view of a flapper section of a subsurfacesafety valve having an expansion tool and an unexpanded tubular disposedtherein;

[0023]FIG. 5 is a section view of the embodiment shown in FIG. 4,wherein the tubular is expanded;

[0024]FIG. 6 is a section view of a flapper type surface controlledsubsurface safety valve, having an expanded tubular according to anembodiment of the invention disposed therein; and

[0025]FIG. 7 is a section view of a ball type surface controlledsubsurface safety valve, having an expanded tubular according to anembodiment of the invention disposed therein.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT

[0026]FIG. 2 is a perspective view of an embodiment of an unexpandedlockout sleeve 10 according to the invention. The lockout sleeve 10 hasa generally tubular body having an outer diameter (OD), an innerdiameter (ID), and a predetermined length L1. The lockout sleeve 10 ispreferably made of a ductile material having sufficient properties toresist forces designed to yield the lockout sleeve, yet able toplastically and/or elastically deform during application of such forcesto a larger diameter without breaking or rupturing. Preferably, thelockout sleeve 10 has a plurality of slots 16 formed in its wall 18.Alternatively, the lockout sleeve may be a solid tubular without anysurface features or have a single longitudinal slot extending the length(L1) of the sleeve. The slots 16 are preferably arranged in alongitudinal pattern in an overlapping fashion to facilitate expansion.However, it should be understood that the slots 16 may be anyappropriate shape of configuration to enable the lockout sleeve 10 toexpand with the application of a radial force. Other surface featuresinclude slits, ellipses, ovals, holes, perforations, irregular shapes,such as dog bone slots, or combinations thereof.

[0027] Prior to expansion of the lockout sleeve, the outside diameter 12of the lockout sleeve 10 is substantially equal to or less than themaximum diameter that will drift to a desired location in the wellbore.After expansion of the sleeve, the inside diameter 14 of the lockoutsleeve 10 is preferably greater than or equal to the drift diameter ofthe wellbore.

[0028]FIG. 3 is a perspective view of an embodiment of an expandedlockout sleeve 10 according to the present invention. The expanded slots16 form a diamond shape as the lockout sleeve 10 is expanded. In use,the expansion tool 100 is lowered into the wellbore (not shown) to apredetermined position and thereafter pressurized fluid is provided inthe run-in tubular 130. In the preferred embodiment, some portion of thefluid is passed through an orifice or some other pressure increasingdevice and into the expansion tool 100 where the fluid urges the rollers116 outwards to contact the wall of the tubular, or lockout sleeve 10,therearound. The expansion tool 100 exerts forces against the wall ofthe lockout sleeve 10 therearound while rotating and, optionally, movingaxially within the wellbore. The result is the lockout sleeve isexpanded past its elastic limits along at least a portion of its outsidediameter. Gravity and the weight of the components urges the expansiontool 100 downward in the wellbore even as the rollers 116 of theexpander tool 100 are actuated. The expansion can also take place in a“bottom up” fashion by providing an upward force on the run-in tubularstring. A tractor (not shown) may be used in a lateral wellbore or insome other circumstance when gravity and the weight of the componentsare not adequate to cause the actuated expansion tool 100 to movedownward along the wellbore. The run-in string of tubulars may includecoiled tubing and in that instance, a mud motor may be utilized adjacentthe expansion tool to provide rotational force to the tool. Thestructure of mud motors is well known. The mud motor can be a positivedisplacement Moineau-type device and includes a lobed rotor that turnswithin a lobed stator in response to the flow of fluids under pressurein the coiled tubing string. The mud motor provides rotational force torotate the expansion tool in the wellbore while the rollers are actuatedagainst an inside surface of a tubular therearound. Additionally, therun-in string may be replaced by wire (or e-line) line providingelectrical energy to an electrical motor and also having the strength tohold the weight of the appartus in the wellbore. In this embodiment, theelectrical motor runs a downhole pump providing a source of pressurizedfluid to an expander tool, tractor and/or a mud motor.

[0029]FIG. 4 is a section view of a flapper section 34 of a subsurfacesafety valve 39 having an expansion tool 100 and an unexpanded lockoutsleeve 10 disposed therein. The lockout sleeve 10 and expansion tool 100are disposed on the end of a run-in string 130, or coil tubing, whichmay be used to provide hydraulic fluid to the expansion tool 100. Thelockout sleeve 10 and expansion tool 100 are shearably connected and areplaced in the wellbore as an assembly. The assembly is lowered to adesired location within the safety valve 39. The flapper section 34 ofthe safety valve 39 rotates about a hinge pin 36 (shown in an openposition). Once the assembly is located at the desired location in thewellbore, the flapper section 34 is opened by the downward force of theassembly on the flapper section 34. Fluid pressure to actuate therollers 116 of the expansion tool 100 is provided from the surface ofthe well through the run-in string 130. The rollers 116 are thenactuated and extended radially outward to contact the inner diameter 14of the lockout sleeve 10. The lockout sleeve 10 is then expanded intosubstantial contact with the inner diameter of the safety valve 39.

[0030]FIG. 5 is a section view of the embodiment shown in FIG. 4,wherein the lockout sleeve 10 is expanded into substantial contact withan inner diameter of the safety valve 39. The lockout sleeve 10 in itsexpanded condition is substantially greater than or equal to thesmallest inner diameter of the safety valve 39 or a tubular (not shown)disposed between the safety valve 39 and the wellbore. This allows thelocked out safety valve 39 to maintain its full open inner diameter andensure that no flow capacity is lost with the addition of the lockoutsleeve.

[0031]FIG. 6 is a section view of a flapper type surface controlledsubsurface safety valve 30, having an expanded lockout sleeve 10disposed therein. Hydraulic fluid is provided to the safety valve 30 viaa control line 34 operated by a control panel 32 on the earth's surface.A valve operator 35, such as a rod piston, moves downward in response toincreasing fluid pressure in the control line 34. A flow tube 40 movesdownward in tandem with the movement of the valve operator 35, therebyopening the flapper 34. A return means 38, such as a spring, a gascharge, or a combination thereof, biases the safety valve 30 in theclosed position by acting to urge the flow tube 40 upwards, opposing theforce of hydraulic pressure. Lowering (or loss of) the hydraulic fluidpressure in the control line 34 serves to move the flow tube 40 upwardsthereby closing the safety valve 30. The lockout sleeve 10 has beenexpanded into a recess 42 above the flow tube 40, thereby prohibiting anupward movement of the flow tube 40. This causes the flapper to remainin the open position, permanently locking out the safety valve 30.

[0032]FIG. 7 is a section view of a ball type surface controlledsubsurface safety valve, having an expanded tubular according to theinvention disposed therein. A valve operator 35, such as an annularpiston, moves downward in response to increasing fluid pressure in thecontrol line 34. A flow tube 40 moves downward in tandem with themovement of the valve operator 35, thereby rotating and opening the ballclosure mechanism 44. A return means 38, such as a spring, a gas charge,or a combination thereof, biases the safety valve 31 to the closedposition by acting to move the flow tube 40 upwards, opposing the forceof hydraulic pressure. Reduced hydraulic fluid pressure in the controlline 34 serves to move the flow tube 40 upwards thereby closing thesafety valve 30. The lockout sleeve 10 has been expanded into a recess42 above the flow tube 40, thereby preventing any upward movement of theflow tube 40. This causes the ball 44 to remain in the open position,permanently locking out the safety valve 30.

[0033] As illustrated by the forgoing, the present invention solvesproblems associated with wellbore valves, especially subsurface safetyvalves by providing an easy means to permanently opening the valveswithout substantially restricting the flow capacity of the valve.

[0034] While the foregoing is directed to the preferred embodiment ofthe present invention, other and further embodiments of the inventionmay be devised without departing from the basic scope thereof, and thescope thereof is determined by the claims that follow.

1. A locking assembly for a wellbore valve, comprising: a cylindricalsleeve, the sleeve insertable into a valve body when unexpanded andconstructed and arranged to interfere with a closing mechanism of thevalve body when expanded.
 2. The locking assembly of claim 1, whereinthe sleeve includes walls with at least one aperture formed therein. 3.The locking assembly of claim 2, wherein the at least one aperture isslot-shaped prior to expansion and diamond-shaped after expansion of thesleeve.
 4. The locking assembly of claim 3, wherein the at least oneaperture facilitates the expansion of the sleeve.
 5. The lockingassembly of claim 1, further including means for expanding the walls ofthe sleeve with an outward, radial force.
 6. The locking assembly ofclaim 1, wherein the expanded sleeve directly interferes with theclosing mechanism.
 7. The locking assembly of claim 1, wherein theexpanded sleeve indirectly interferes with the closing mechanism.
 8. Amethod of locking a wellbore valve in an open position, the methodcomprising: inserting a cylindrical sleeve into an interior of thevalve; and expanding the sleeve within the interior whereby the expandedsleeve interferes with a closing mechanism of the valve, thereby lockingthe valve in an open position.
 9. The method of claim 8, furtherincluding opening the valve prior to insertion of the sleeve.
 10. Themethod of claim 8, further including inserting an expander tool into aninterior of the sleeve.
 11. The method of claim 10, wherein the expandertool includes outwardly extending fluid actuated members.
 12. The methodof claim 11, wherein the sleeve is expanded by radial pressure of themembers on an interior surface of the sleeve.
 13. The method claim 8,wherein the sleeve is expanded into direct contact with a closingmechanism.
 14. The method of claim 8, wherein the sleeve is expandedinto indirect contact with the closing mechanism.
 15. The method ofclaim 8, wherein the valve is a flapper valve.
 16. The method of claim8, wherein the valve is a ball valve.
 17. A lockout sleeve for a safetyvalve in a wellbore, comprising: an expandable tubular having an outerdiameter substantially equal to or less than a drift diameter of thewellbore.
 18. The apparatus of claim 17, wherein an inner diameter ofthe tubular is expandable to a diameter substantially equal to orgreater than the drift diameter of the wellbore.
 19. The apparatus ofclaim 18, wherein the tubular is a ductile material.
 20. The apparatusof claim 17, wherein the tubular has one or more surface features. 21.The apparatus of claim 20, wherein the one or more surface features areslots, slits, holes, ovals, diamonds, perforations, or a combinationthereof.
 22. A method for locking out a safety valve in a wellbore,comprising: placing a tubular in the wellbore; placing an expansion toolin the wellbore; landing the tubular and the expansion tool adjacent thesafety valve; positioning the tubular and the expansion tool within aninner diameter of the safety valve; energizing the expansion tool andcausing extendable members therein to extend radially to contact aninner diameter of the tubular; and expanding the tubular intosubstantial contact with the inner diameter of the safety valve.
 23. Themethod of claim 22, wherein the tubular is expanded to a diametersubstantially equal to or greater than the drift diameter of thewellbore.
 24. The method of claim 22, wherein the safety valve ismechanically opened prior to positing the tubular and the expansion toolwithin the inner diameter of the safety valve.
 25. The method of claim22, wherein the tubular and the expansion tool are placed in thewellbore on a run-in string of tubulars.
 26. The method of claim 25,wherein the run-in string of tubulars is a coiled tubing.
 27. A methodfor locking out a safety valve in a wellbore, comprising: placing atubular in the wellbore, the tubular having an outer diametersubstantially equal to or less than a drift diameter of the wellbore;placing an expansion tool in the wellbore; landing the tubular and theexpansion tool adjacent the safety valve; locating a flow tube disposedwithin the valve; positioning the tubular and the expansion tool withinan inner diameter of the safety valve; energizing the expansion tool andcausing extendable members therein to extend radially to contact aninner diameter of the tubular; and expanding the tubular intosubstantial contact with the inner diameter of the safety valve adjacentthe flow tube.
 28. The method of claim 27, wherein the tubular isexpanded to a diameter substantially equal to or greater than the driftdiameter of the wellbore.
 29. The method of claim 27, wherein the safetyvalve is mechanically opened prior to positing the tubular and theexpansion tool within the inner diameter of the safety valve.
 30. Themethod of claim 27, wherein the tubular and the expansion tool areplaced in the wellbore on a run-in string of tubulars.
 31. The method ofclaim 29, wherein the run-in string of tubulars is a coiled tubing.